Hydroxyl group-containing amine-boron adducts as reduced odor catalyst compositions for the production of polyurethanes

ABSTRACT

An amine-boron composition for catalyzing the urethane reaction, particularly in preparing a polyurethane foam, consisting essentially of the addition product of a tertiary amine and a boron compound of the formula 
     
         R.sub.n B(OH).sub.3-n 
    
     where 
     n=0 or 1, and 
     R=C 1  -C 8  alkyl, C 5  -C 8  cycloalkyl or C 6  -C 10  aryl. 
     Preferred catalysts are prepared by mixing triethylenediamine or 3-quinuclidinol with boric acid.

The present application is a division of application Ser. No. 839,519,filed on Feb. 20, 1992 and now U.S. Pat. No. 5,166,223, which is acontinuation-in-part of Ser. No. 829,786, filed on Jan. 31, 1992 and nowU.S. Pat. No. 5,162,379, which is a continuation-in-part of Ser. No.763,107, filed on Sep. 20, 1991 and now U.S. Pat. No. 5,086,081.

FIELD OF THE INVENTION

The present invention relates to the use of tertiary amines as catalystsfor producing polyurethanes.

BACKGROUND OF THE INVENTION

The commercial production of polyurethanes via isocyanate polyadditionreactions requires the use of catalysts. Tertiary amines were widelyaccepted in the industry as versatile polyurethane catalysts. They aregenerally stable in the presence of standard polyurethane formulationcomponents and can impact both the blowing (water-isocyanate) andgelling (polyol-isocyanate) reactions. Unfortunately, a number ofcommonly used tertiary amine catalysts are relatively volatile and havean unpleasant smell. Even at low use levels, they may impart anoticeably pungent odor to the polyurethane formulation. It would bedesirable to identify alternatives to standard tertiary amine catalystswhich are not malodorous, yet exhibit the same type of activity inisocyanate polyaddition reactions.

One strategy for the reduction of odor associated with tertiary aminecatalysts is the identification of less volatile structures. Theliterature teaches numerous techniques for reducing volatility,particularly increasing molecular weight or improving hydrogen bondingcapability.

U.S. Pat. No. 4,026,840 describes the use of hydroxy-functional tertiaryamines as polyurethane catalysts, particularly useful for the productionof polyisocyanurate. In addition to lower volatility, such materialsalso contain reactive functionality which binds the amine into the finalproduct. Typically, however, catalysts which are non-fugitive by way ofreaction with isocyanate must be used at relatively high levels tocompensate for immobilization of the tertiary amine functionality duringurethane part production.

U.S. Pat. No. 4,006,124 which is an example of lower volatility beingachieved by metal complex formation, describes the use of amidine-metalcomplexes as polyurethane catalysts.

U.S. Pat. No. 4,857,560 mentions reduced odor emission as an additionaladvantage of the disclosed expansion catalysts formed from tertiaryamines and an acid mixture of (1) boric acid and (2) a carboxylic acid.Unfortunately, strong organic acid containing catalysts tend to showmasterbatch instability and corrosivity. Furthermore, carboxylic acidfunctionality is reactive with and can consume expensive isocyanatefunctionality, resulting in the formation of amide rather than the morestandard urethane or urea segments in a resulting part.

Boric acid derivatives have not otherwise been used in combination withtertiary amines to effect amine odor reduction. Other uses of boric acidin polyurethane formulations, however, have been described.

CA 99(6):39229a notes that boric acid, when used as a filler at 10-40%,decelerates foaming in polyurethanes based on Laprol 805 and Lapramol294 polyether polyols, polyisocyanate, Freon 113 and water.

"Int. Prog. Urethanes 1980", 2, 153-73 describes the use of boric acidas a blowing agent, its behavior being almost equal to that of water.Neither reference describes the effect of boric acid at use levelstypified by a catalyst, nor do they indicate the effect of boric acid onpolyurethane catalysis in the presence of a tertiary amine.

U.S. Pat. No. 4,611,013 describes the use of quarternary ammoniumborates to effect the concurrent trimerization/carbodiimidization ofpolyisocyanates. The borates are prepared from boric acid, alcohols andquarternary ammonium hydroxides and as such are not derived fromtertiary amines. Other examples are given by U.S. Pat. Nos. 4,530,938and 4,425,444.

U.S. Pat. No. 3,193,515; U.S. Pat. No. 3,127,404 and FR 2,301,554disclose the use of boric acid in the preparation of an ammonium saltpolyurethane catalyst from triethylenediamine and a glycol borate acid.Glycol borate acids are prepared by heating mixtures containing notsubstantially less than 0.5 moles of boric acid per mole glycerol oralternative vicinal glycol to effect acid complex formation. Theadvantage of such catalyst composition is delayed activity and/oraccelerated cure. Unfortunately, the preferred catalyst compositions arehighly viscous because a low glycol/boric acid ratio is required tominimize the amount of glycol delivered into a formulation. The additionof low molecular weight glycol into polyurethane parts, particularlyfoam parts, is typically avoided to prevent unnecessary consumption ofexpensive isocyanate. Further, glycols can negatively impact physicalproperties.

"J. Org. Chem." 1972, 37 (14), 2232 discloses that monodentate nitrogennucleophiles do not react significantly with boric acid in aqueoussolution.

SUMMARY OF THE INVENTION

The present invention provides a composition for catalyzing thetrimerization of an isocyanate and/or the reaction between an isocyanateand a compound containing a reactive hydrogen, e.g. the urethanereaction for making polyurethane. The catalyst composition consistsessentially of a tertiary amine urethane catalyst in combination with aboron compound of the formula

    R.sub.n B(OH).sub.3-n

where

n=0 or 1, and

R=C₁ -C₁ -C₈ alkyl, C₅ -C₈ cycloalkyl or C₆ -C₁₀ aryl.

The tertiary amine may contain reactive functionality, such as hydroxylgroups.

As an advantage of these catalyst compositions there is a significantreduction in amine odor compared to standard polyurethane catalystcompositions containing volatile tertiary amines. The odor reduction isattributed to a reduced vapor pressure for the tertiary amine in thepresence of the boron compound and suggests that the use of these newamine-boron compositions will help to minimize worker exposure to aminecatalysts during polyurethane foam production. This is an importantadvantage since tertiary amines can have adverse health effects. Oneexample of an adverse health effect is the temporary condition termed"halo vision" which has been reported in connection with worker exposureto bis(dimethylaminoethyl) ether, an industry standard catalyst for thereaction of water with an isocyanate. Other symptoms of exposure toamine catalysts are lacrimation, conjunctivitis, nausea and respiratoryirritation.

Improved reactivities and physical properties have been noted when suchamine-boron compositions are used as catalysts for isocyanatepolyaddition reactions.

In catalyst compositions containing reactive (e.g. hydroxyl groups)tertiary amines and a boron compound, an additional advantage is thatdesired catalyst performance is achieved at lower amine use level.

Other distinct advantages over boron-containing prior art catalystcompositions include reduced viscosity and lower corrosivity.

DETAILED DESCRIPTION OF THE INVENTION

The catalyst compositions according to the invention can catalyze thereaction between an isocyanate functionality and an activehydrogen-containing compound, i.e. an alcohol, an amine or water,especially the urethane (gelling) reaction to make polyurethanes and theblowing reaction of water with isocyanate to release carbon dioxide formaking foamed polyurethanes, or the trimerization of the isocyanatefunctionality to form polyisocyanurates.

The polyurethane products are prepared using suitable organicpolyisocyanates well known in the art including, for example,hexamethylene diisocyanate, phenylene diisocyanate, toluene diisocyanate("TDI") and 4,4'-diphenylmethane diisocyanate. Especially suitable arethe 2,4- and 2,6-TDIs individually or together as their commerciallyavailable mixtures. Other suitable isocyanates are mixtures ofdiisocyanates known commercially as "crude MDI", also known as PAPI,which contain about 60% of 4,4'-diphenylmethane diisocyanate along withother isomeric and analogous higher polyisocyanates. Also suitable are"prepolymers" of these polyisocyanates comprising a partially prereactedmixture of polyisocyanates and polyether or polyester polyols.

Illustrative of suitable polyols as a component of the polyurethanecomposition are the polyalkylene ether and polyester polyols. Thepolyalkylene ether polyols include the poly(alkylene oxide) polymerssuch as poly(ethylene oxide) and poly(propylene oxide) polymers andcopolymers with terminal hydroxyl groups derived from polyhydriccompounds, including diols and triols; for example, among others,ethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol,1,6-hexane diol, neopentyl glycol, diethylene glycol, dipropyleneglycol, pentaerythritol, glycerol, diglycerol, trimethylol propane andlike low molecular weight polyols.

In the practice of this invention, a single high molecular weightpolyether polyol may be used. Also, mixtures of high molecular weightpolyether polyols such as mixtures of di- and tri-functional materialsand/or different molecular weight or different chemical compositionmaterials may be used.

Useful polyester polyols include those produced by reacting adicarboxylic acid with an excess of a diol, for example, adipic acidwith ethylene glycol or butanediol, or reacting a lactone with an excessof a diol such as reacting caprolactone with propylene glycol.

In addition to the polyether and polyester polyols, the masterbatches,or premix compositions, frequently contain a polymer polyol. Polymerpolyols are used in polyurethane foam to increase the foam's resistanceto deformation, i.e. to increase the load-bearing properties of thefoam. Currently, two different types of polymer polyols are used toachieve load-bearing improvement. The first type, described as a graftpolyol, consists of a triol on which vinyl monomers are graftcopolymerized. Styrene and acrylonitrile are the usual monomers ofchoice. The second type, polyurea modified polyols, is a polyolcontaining a polyurea dispersion formed by the reaction of a diamine andTDI. Since TDI is used in excess, some of the TDI may react with boththe polyol and polyurea. This second type of polymer polyol has avariant called PIPA polyol which is formed by the in-situ polymerizationof TDI and alkanolamine in the polyol. Depending on the load-bearingrequirements, polymer polyols may comprise 20-80% of the polyol portionof the masterbatch.

Other typical agents found in the polyurethane foam formulations includecrosslinkers such as ethylene glycol, butanediol, diethanolamine,diisopropanolamine, triethanolamine and/or tripropanolamine; blowingagents such as water, methylene chloride, trichlorofluoromethane and thelike; and cell stabilizers such as silicones.

A general polyurethane flexible foam formulation containing the catalystcomposition according to the invention would comprise the followingcomponents in parts by weight (pbw):

    ______________________________________                                        Flexible Foam Formulation                                                                   Parts by Weight                                                 ______________________________________                                        Polyol          20-80                                                         Polymer Polyol  80-20                                                         Silicone Surfactant                                                                             1-2.5                                                       Blowing Agent     2-4.5                                                       Crosslinker     0.5-2                                                         Catalyst        0.5-2                                                         Isocyanate Index                                                                               50-115                                                       ______________________________________                                    

The urethane catalyst composition consists essentially of the additionproduct, or adduct, of a tertiary amine urethane catalyst, which cancontain reactive functionality, e.g. hydroxyl groups, and a boroncompound of the general formula:

    R.sub.n B(OH).sub.3-n

where

n is 0 or 1, and

R is C₁ -C₈ alkyl, C₅ -C₈ cycloalkyl or C₆ -C₁₀ aryl.

Alkyl groups in the boron compound would include, for example, methyl,ethyl, butyl, ethylhexyl and the like; cycloalkyl would include, forexample, cyclopentyl, cyclohexyl and the like; and aryl groups wouldinclude, for example, phenyl, p-tolyl and the like.

Exemplary of suitable boron compounds are boric acid, phenylboronic acidand isopropylboronic acid. The preferred boron compound is boric acidwhere n is 0. Contemplated as functional equivalents to boric acid forpurposes of this invention are the borate esters, i.e., alkyl-, dialkyl-and trialkylborates, in which the alkoxy groups hydrolyze to thehydroxyl functionality in the presence of water.

It is also contemplated that any tertiary amine suitable as a urethanecatalyst can be used in making the amine-boron adduct catalystcomposition. Illustrative of suitable tertiary amine urethane catalystsare pentamethyldiethylenetriamine, pentamethyldipropylenetriamine,bis(dimethylaminoethyl) ether, dimethylcyclohexylamine,triethylenediamine ("TEDA"), 4-dimethylaminopyridine,diazabicyclo[5.4.0]undec-7-ene, diaz cyclo[4.3.0]non-5-ene,N-ethylmorpholine, N-methylmorpholine, N-cetyl-N,N-dimethylamine,N-cocomorpholine, N-(N,N-dimethylaminoethyl)morpholine,tris(3-dimethylamino-propyl)amine and the like.

The suitable tertiary amine urethane catalyst may also contain hydroxyfunctionality. Illustrative of tertiary amines containing reactivefunctionality are N,N,N'-trimethyl-N'-hydroxyethylethylenediamine,N,N-dimethylethanolamine,N,N,N'-L-trimethyl-N'-hydroxyethylbis(aminoethyl)ether, 3-quinuclidinol(also known as 3-hydroxyazabicyclo[2.2.2]octane) and the like. Thepreferred 3-quinuclidinol has the following formula I: ##STR1##

Typical molar ratios of tertiary nitrogen to boron in making thecatalyst composition are from 1:0.01 to 1:100, preferably 1:0.1 to 1:10,most preferably 1:0.5 to 1:2 for acyclic amines, 1:0.5 to 1:1 for TEDAand 1:0.5 to 1:1 for 3-quinuclidinol.

Such catalyst compositions are generally easily handled solids which areprepared by precipitation from appropriate solvents upon mixing thetertiary amine with the boron compound at temperatures from ambient (orlower) to about 50° C., i.e. without substantial heating, and anyconvenient pressure, especially atmospheric pressure. In addition, solidadducts are afforded upon mixing the tertiary amine and the boric acidin a on-solvent for the adduct, again without the need for substantialheating. For example, TEDA and boric acid can be lended intetrahydrofuran or 2-(2-methoxyethoxy)ethanol to yield a solid product.

The amine-boron adducts are also easily prepared and more convenientlydelivered as solutions in carriers such as water, alcohols, polyols,amines, polyamines, ethers, hydrocarbons and chlorinated hydrocarbons.The preferred carriers are water, alcohols and polyols. The morepreferred carriers are standard polyurethane additives such as water,crosslinkers (e.g., diethanolamine), chain extenders (e.g., butanediol),and higher molecular weight polyether and polyester polyols. When usingphenylboronic acid, it is preferred first to dissolve the tertiary aminein the carrier and then add the phenylboronic acid.

A catalytically effective amount of the catalyst composition is used inthe polyurethane formulation. More specifically, suitable amounts of thecatalyst composition may range from about 0.01 to 10 parts per 100 partspolyol in the polyurethane formulation.

The catalyst compositions may be used in combination with other tertiaryamine and organotin urethane catalysts well known in the urethane art.

These catalyst compositions have the advantage of substantially reducedamine odor relative to standard tertiary amines while exhibitingcomparable or improved catalytic activity. Significantly improvedcatalytic activity has been noted for reactive amine-boron combinations.The catalyst composition also manifests reduced viscosity and lowercorrosivity.

The following automotive formulation master batches were used in theExamples:

    ______________________________________                                        Automotive Formulation Master Batch I                                         PLURACOL 816 (conventional polyether polyol)                                                             40 pphp                                            PLURACOL 1003 (styrene-acrylonitrile filled                                                              60                                                 polymer polyol)                                                               DC 5243 (silicone surfactant)                                                                             1.2                                               DEOA-LF (85 wt % diethanolamine in water)                                                                 1.75                                              Automotive Formulation Master Batch II                                        Multranol 9143 (conventional polyether polyol)                                                           50 pphp                                            Multranol 9151 (PHD filled polymer polyol)                                                               50                                                 DC 5043 (silicone surfactant)                                                                             1.75                                              DEOA-LF                     2.0                                               Automotive Formulation Master Batch III                                       Pluracol 816               60 pphp                                            Pluracol 973 (styrene-acrylonitrile filled                                                               40                                                 polyether polyol)                                                             DC 5043                     1.5                                               DEOA-LF                     1.76                                              ______________________________________                                    

EXAMPLE 1

A 1:2 molar mixture of BL22 catalyst (a 70:30 wt/wt mixture ofpentamethyldiethylenetriamine and pentamethyldipropylene-triamine) andboric acid was prepared according to the following procedure. BL22catalyst (25 g), boric acid (17 g), and water (42 g) were combined anddissolved at room temperature over 30 min. The resulting solution hadminimal, if any, amine odor.

EXAMPLE 2

A 1:3 molar mixture of BL22 catalyst and boric acid was preparedaccording to the following procedure. BL22 catalyst 25 g), boric acid(26 g), and water (51 g) were combined and dissolved at room temperatureover 30 min. The resulting solution had minimal, if any, amine odor.

EXAMPLE 3

A 1:2 molar mixture of triethylenediamine ("TED") and phenylboronic acidwas prepared by cOmbining TEDA (1.25 g), phenylboronic acid (2.75 g),ethylene glycol (6.2 g) and diethylene glycol (9.8 g) and dissolvingwith mild heating (˜40° C.) over several minutes. The resulting solutionhad minimal, if any, amine odor.

EXAMPLE 4

A 1:2 molar mixture of TEDA and boric acid was prepared by combiningTEDA (118.5 g), boric acid (131.1 g) and water (250 g) and dissolving atroom temperature over 30 min.

EXAMPLE 5

A 1:2 molar mixture of pentamethyldiethylenetriamine (Polycat®5) andboric acid was prepared by combining pentamethyldiethylenetriamine (260g), boric acid (186.4 g) and water (446.4 g) and dissolving at roomtemperature over 30 min. The resulting solution had minimal, if any,amine odor.

EXAMPLE 6

A 1:2 molar mixture of pentamethyldipropylenetriamine (Polycat 77) andboric acid was prepared by combining pentamethyldipropylenetriamine(292.5 g), boric acid (180.4 g) and water (472.9 g) and dissolving atroom temperature over 30 min. The resulting solution had minimal, ifany, amine odor.

EXAMPLE 7

A 1:2 molar mixture of bis(dimethylaminoethyl)ether (DABCO BL-19) andboric acid was prepared by combining bis(dimethylaminoethyl)ether (50g), boric acid (38.8 g) and water (88.8 g) and dissolving at roomtemperature over 30 min. The resulting solution had minimal, if any,amine odor.

The following Comparative Example 8 to Example 24 demonstrate that thesereduced odor amine-boron compositions exhibit equivalent or improvedreactivity when compared to standard tertiary amine catalysts for theproduction of flexible molded polyurethane foam. Foams prepared usingthe new catalyst compositions have physical properties which comparewell to those for foams prepared using industry standard catalysts.

COMPARATIVE EXAMPLE 8 AND EXAMPLE 9

PHD polyol based formulations were prepared from master batchformulation II in which the DEOA-LF level was 1.75 pphp, 2.8 pphp waterand (a) 0.50 pphp DABCO 33LV® catalyst with 0.12 pphp DABCO® BL-11catalyst as the Comparative Example 8 control catalyst or (b) 1.2 pphpof a 50 wt % aqueous solution of 1:2 TEDA and boric acid (TEDA:BA) ofthe Example 4 catalyst. Foams were prepared on an Elastogram PU-20machine by combining each of the above formulations with an 80:20mixture of 2,4- and 2,6-TDI at a 1.05 molar ratio of isocyanate toactive hydrogen functionality in a 140° F. (60° C.) mold for 4 min.Catalyst performance and physical properties are given in Table A.

                  TABLE A                                                         ______________________________________                                                        DABCO                                                         Catalyst        33LV/BL-11 TEDA:BA                                            ______________________________________                                        Initiation time.sup.a (sec)                                                                   5.83.sup.b 5.80.sup.c                                         Extrustion time (sec)                                                                         31.04.sup.b                                                                              30.91.sup.c                                        String Gel time (sec)                                                                         42.64.sup.b                                                                              39.85.sup.c                                        Extrusion weight (g)                                                                          41.sup.b   16.9.sup.c                                         Pad weight (g)  628.4.sup.b                                                                              606.6.sup.c                                        ILD-25%         34.8.sup.c 35.0.sup.c                                         ILD-65%         110.0.sup.c                                                                              105.8.sup.c                                        ILD-25% R       28.0.sup.c 28.3.sup.c                                         Density (lb/ft.sup.3)                                                                         2.07.sup.c 2.09.sup.c                                         Airflow (ft.sup.3 /min)                                                                       1.36.sup.c 1.50.sup.c                                         Tear (psi)      1.47.sup.c 1.53.sup.c                                         Tensile (psi)   16.95.sup.c                                                                              19.21.sup.c                                        Strain (%)      76.98.sup.c                                                                              90.71.sup.c                                        Ball Rebound (in)                                                                             45.00.sup.c                                                                              49.50.sup.c                                        Compression set 50%                                                                           7.96.sup.c 8.07.sup.c                                         ______________________________________                                         .sup.a cream time                                                             .sup.b average of three shot sizes4.00, 3.85 and 3.60 sec                     .sup.c average for foams poured at minimum fill (3.60 sec shot)          

COMPARATIVE EXAMPLES 10-11 AND EXAMPLES 12-14

SAN polyol based formulations were prepared from master batchformulation III, 3.5 pphp total water, and a) 0.50 pphp DABCO 33-LVcatalyst with 0.15 pphp DABCO BL-11 catalyst as the Comparative Example10 control catalyst, b) 0.50 pphp DABCO 33-LV catalyst with 0.19 pphpDABCO BL-17 catalyst as Comparative Example 11 control catalyst, or c)0.50 pphp DABCO 33-LV with varying levels of the catalysts prepared inExamples 5-7. The formulations were mixed well for 30 sec immediatelyprior to adding 43.3 pphp of an 80:20 mixture of 2,4- and 2,6-TDI (1.05molar ratio of isocyanate to active hydrogen functionality). Aftermixing well for 4 sec, the foam was allowed to rise freely at roomtemperature. Full foam height was measured immediately and again afteraging for 24h. Foam recession is the percent difference between thefinal foam height measurement and the initial foam height measurement.Catalyst use levels and performance data are given in Table B.

                                      TABLE B                                     __________________________________________________________________________            Example #                                                                                   Example 12                                                                          Example 13                                                                          Example 14                                          Comp   Comp   33-LV/                                                                              33-LV/                                                                              33-LV/                                      Catalyst                                                                              Example 10                                                                           Example 11                                                                           Example 5                                                                           Example 6                                                                           Example 7                                   Comb    33-LV/BL-11                                                                          33-LV/BL-17                                                                          catalyst                                                                            catalyst                                                                            catalyst                                    __________________________________________________________________________    DABCO 33-LV                                                                           0.50   0.50   0.50  0.50  0.50                                        DABCO BL-11                                                                           0.15                                                                  DABCO BL-17    0.19                                                           Example 5             0.54                                                    catalyst                                                                      Example 6                   1.01                                              catalyst                                                                      Example 7                         0.39                                        catalyst                                                                      top of cup 1                                                                          9.76   12.42  11.04 11.45 10.68                                       top of cup 2                                                                          27.60  32.00  30.15 31.91 30.95                                       string gel                                                                            44.73  49.31  44.27 45.29 46.52                                       full rise                                                                             67.29  72.43  69.08 69.14 72.66                                       % recession                                                                           7.1           7.0   8.3   7.0                                         __________________________________________________________________________

COMPARATIVE EXAMPLE 15

The control catalysts, 0.35 pphp DABCO 33LV catalyst (containing 33 wt %TEDA and 67 wt % dipropylene glycol) and 0.24 pphp BL22 catalyst, and2.9 pphp water (3.2 pphp total water) were added to automotiveformulation master batch I and mixed well for 30 sec immediately priorto adding 41.6 pphp of an 80:20 mixture of 2,4- and 2,6-TDI (1.05 molarratio of isocyanate to active hydrogen functionality). After mixing wellfor 4 sec, the foam was allowed to rise freely at room temperature. Fullfoam rise height was measured immediately and again after aging for 24h.

    ______________________________________                                        top of cup 1 (sec)                                                                              9.33                                                        top of cup 2 (sec)                                                                              26.13                                                       string gel (sec)  45.49                                                       full rise (sec)   60.38                                                       initial full rise (mm)                                                                          407.56                                                      final full rise (mm)                                                                            367.52                                                      ______________________________________                                    

EXAMPLE 16

An experimental catalyst, 0.81 pphp of a 50 wt % aqueous solution of 1:2BL22 catalyst and boric acid prepared according to Example 1 (equivalentto 0.24 pphp BL22 catalyst), 0.35 pphp DABCO 33LV catalyst, and 2.5 pphpwater (3.2 pphp total water) were added to master batch formulation Iand mixed well for 30 sec immediately prior to adding 41.6 pphp of an80:20 mixture of 2,4- and 2,6-TDI (1.05 molar ratio of isocyanate toactive hydrogen functionality). After mixing well for an additional 4sec, the foam was allowed to rise freely at room temperature. Full foamrise height was measured immediately and again after aging for 24h.

    ______________________________________                                        top of cup 1 (sec)                                                                              9.90                                                        top of cup 2 (sec)                                                                              26.50                                                       string gel (sec)  47.14                                                       full rise (sec)   58.77                                                       initial full rise (mm)                                                                          409.22                                                      final full rise (mm)                                                                            347.25                                                      ______________________________________                                    

EXAMPLE 17

An experimental catalyst, 0.98 pphp of a 50 wt % aqueous solution of 1:3BL22 catalyst and boric acid prepared according to Example 2 (equivalentto 0.24 pphp BL22 catalyst), 0.35 pphp DABCO 33LV catalyst, and 2.4 pphpwater (3.2 pphp total water) were added to master batch formulation Iand mixed well for 30 sec immediately prior to adding 41.6 pphp of an80:20 mixture of 2,4- and 2,6-TDI (1.05 molar ratio of isocyanate toactive hydrogen functionality). After mixing well for 4 sec, the foamwas allowed to rise freely at room temperature. Full foam rise heightwas measured immediately and again after aging for 24h.

    ______________________________________                                        top of cup 1 (sec)                                                                              10.73                                                       top of cup 2 (sec)                                                                              28.27                                                       string gel (sec)  46.92                                                       full rise (sec)   61.46                                                       initial full rise (mm)                                                                          409.68                                                      final full rise (mm)                                                                            348.19                                                      ______________________________________                                    

COMPARATIVE EXAMPLE 18

The control catalysts, 0.35 pphp DABCO 33LV catalyst and 0.24 pphp BL22catalyst, and 2.9 pphp water (3.2 pphp total water) were added to masterbatch formulation I and allowed to age for 15h, then mixed well for 30sec immediately prior to adding 41.6 pphp of an 80:20 mixture of 2,4-and 2,6-TDI (1.05 molar ratio of isocyanate to active hydrogenfunctionality). After mixing well for an additional 4 sec, the foam wasallowed to rise freely at room temperature. Full foam rise height waseasured immediately and again after aging for 24h.

    ______________________________________                                        top of cup 1 (sec)                                                                              9.68                                                        top of cup 2 (sec)                                                                              26.29                                                       string gel (sec)  44.79                                                       full rise (sec)   59.05                                                       initial full rise (mm)                                                                          409.14                                                      final full rise (mm)                                                                            367.54                                                      ______________________________________                                    

EXAMPLE 19

An experimental catalyst, 0.81 pphp of a 50 wt % aqueous solution of 1:2BL22 catalyst and boric acid prepared according to Example 1 (equivalentto 0.24-pphp BL22 catalyst), 0.35 pphp DABCO 33LV catalyst, and 2.5 pphpwater (3.2 pphp total water) were added to master batch formulation Iand allowed to age for 15h, then mixed well for 30 sec immediately priorto adding 41.6 ppph of an 80:20 mixture of 2,4- and 2,6-TDI (1.05 molarratio of isocyanate to active hydrogen functionality). After mixing wellfor an additional 4 sec, the foam was allowed to rise freely at roomtemperature. Full foam rise height was measured immediately and againafter aging for 24h.

    ______________________________________                                        top of cup 1 (sec)                                                                              10.89                                                       top of cup 2 (sec)                                                                              28.00                                                       string gel (sec)  47.64                                                       full rise (sec)   59.94                                                       initial full rise (mm)                                                                          412.86                                                      final full rise (mm)                                                                            356.48                                                      ______________________________________                                    

EXAMPLE 20

An experimental catalyst, 0.98 pphp of a 50 wt % aqueous solution of 1:3BL22 catalyst and boric acid prepared according to Example 2 (equivalentto 0.24 pphp BL22 catalyst), 0.35 pphp DABCO 33LV catalyst, and 2.4 pphpwater (3.2 pphp total water) were added to master batch formulation Iand allowed to age for 15h, then mixed well for 30 sec immediately priorto adding 41.6 pphp of an 80:20 mixture of 2,4- and 2,6-TDI (1.05 molarratio of isocyanate to active hydrogen functionality). After mixing wellfor 4 sec, the foam was allowed to rise freely at room temperature. Fullfoam rise height was measured immediately and again after aging for 24h.

    ______________________________________                                        top of cup 1 (sec)                                                                              11.93                                                       top of cup 2 (sec)                                                                              30.19                                                       string gel (sec)  52.20                                                       full rise (sec)   63.47                                                       initial full rise (mm)                                                                          411.90                                                      final full rise (mm)                                                                            356.37                                                      ______________________________________                                    

COMPARATIVE EXAMPLE 21

The control catalysts, 0.35 pphp DABCO 33LV catalyst and 0.24 pphp BL22catalyst, and 2.9 pphp water (3.2 pphp total water) were added to masterbatch formulation I and allowed to age for 15h, then mixed well for 30sec immediately prior to adding 41.6 pphp of an 80:20 mixture of 2,4-and 2,6-TDI (1.05 molar ratio of isocyanate to active hydrogenfunctionality). After mixing well for 4 sec, the mixture was poured over11 sec into a five vent mold heated to 140° F. (60° C.), and allowed tocure for 4 min prior to demold.

    ______________________________________                                        extrusion (sec) 27.21                                                         string gel (sec)                                                                              36.26                                                         foam weight (g) 180.2                                                         ______________________________________                                    

EXAMPLE 22

An experimental catalyst, 0.81 pphp of a 50 wt% aqueous solution of 1:2BL22 catalyst and boric acid prepared according to Example 1 (equivalentto 0.24 pphp BL22 catalyst), 0.35 pphp DABCO 33LV catalyst, and 2.5 pphpwater (3.2 pphp total water) were added to master batch formulation Iand allowed to age for 15h, then mixed well for 30 sec immediately priorto adding 41.6 pphp of an 80:20 mixture of 2,4- and 2,6-TDI (1.05 molarratio of isocyanate to active hydrogen functionality). After mixing wellfor 4 sec, the mixture was poured over 11 sec into a five vent moldheated to 140° F. (60° C.), and allowed to cure for 4 min prior todemold.

    ______________________________________                                        extrusion (sec) 27.99                                                         string gel (sec)                                                                              38.83                                                         foam weight (g) 174.0                                                         ______________________________________                                    

COMPARATIVE EXAMPLE 23

The control catalysts, 0.35 pphp DABCO 33LV catalyst and 0.15 pphp DABCOBL-11 catalyst, and 2.9 pphp water (3.2 pphp total water) were added tomaster batch formulation II and mixed well for 30 sec prior to adding42.0 pphp of an 80:20 mixture of 2,4- and 2,6-TDI (1.05 molar ratio ofisocyanate to active hydrogen functionality). After mixing well for 4sec, the mixture was poured over 11 sec into a five vent mold heated to140° F. (60° C.), and allowed to cure for 4 min prior to demold.

    ______________________________________                                        extrustion (sec)  34.75                                                       string gel (sec)  44.17                                                       foam weight (g)   189.6                                                       residual weight (g)*                                                                            46.4                                                        extrusion weight (g)                                                                            28.0                                                        ______________________________________                                         *weight of foam remaining in the cup after pouring into the mold         

EXAMPLE 24

As experimental catalyst, 0.59 pphp of a 20 wt % solution of 1:2 TEDAand phenylboronic acid in a diethylene glycol/ethylene glycol mixtureprepared according to Example 3, 0.25 pphp DABCO 33LV catalyst, 0.15pphp DABCO BL-II catalyst, and 2.0 pphp water (3.2 pphp total water)were added to master batch formulation II and mixed well for 30 secprior to adding 42.9 pphp of an 80:20 mixture of 2,4- and 2,6-TDI (1.05molar ratio of isocyanate to active hydrogen functionality). Aftermixing well for 4 sec, the mixture was poured over 11 sec into a fivevent mold heated to 140° F. (60° C.), and allowed to cure for 4 minprior to demold.

    ______________________________________                                        extrustion (sec)  39.63                                                       string gel (sec)  49.43                                                       foam weight (g)   188.4                                                       residual weight (g)*                                                                            45.2                                                        extrusion weight (g)                                                                            32.5                                                        ______________________________________                                         *weight of foam remaining in the cup after pouring into the mold         

Solutions of tertiary amines and the boron compounds R_(n) B(OR')_(3-n)can have much lower viscosity at comparable solids than previouslyreported amine-boron catalyst compositions. Low viscosity compositionsare conveniently handled, whereas highly viscous materials often need tobe heated to enable delivery into a commercial formulation.

COMPARATIVE EXAMPLE 25

The glycerol borate acid salt of TEDA was prepared according to U.S.Pat. No. 3,113,515. Boric acid was combined with 2 molar equivalents ofglycerol and tested to 180° F. to afford a glycerol borate acid. Thereaction mixture was then cooled to 100° F. and treated with 1 molarequivalent of TEDA. Further cooling afforded a viscous materialcontaining 30 wt % TEDA which had a measured Brookfield viscosity of14,800 centipoise at 25° C.

EXAMPLE 26

An aqueous 1:1 TEDA/boric acid molar mixture was prepared by dissolvingTEDA in water and adding 1 molar equivalent of boric acid under ambientconditions. Dissolution of the boric acid was rapid, resulting in amodest exotherm (<50° C.). The resulting solution which was 33 wt % TEDAand 50 wt % solids had a measured Brookfield viscosity of 16 centipoiseat 25° C.

Catalyst compositions of this invention have also been found to benon-corrosive according to a standard static NACE corrosivity test.Comparable strong acid blocked tertiary amine catalysts exhibitvariable, however, typically significant, corrosion of carbon steel.

EXAMPLE 27

A series of tertiary amine/boric acid compositions was evaluated forcorrosivity according to a standard static NACE corrosivity test.Coupons prepared from 1010 carbon steel were partially submerged in thecatalyst solution. Corrosion as measured for the liquid and vapor phasecontact as well as at the liquid/vapor interface. Comparative data wasobtained for several commercially available acid blocked tertiary aminecatalysts. The following Table C summarizes the results.

                  TABLE C                                                         ______________________________________                                        Catalyst Corrosivity                                                          Catalyst      Environment                                                                              Corrosion Rate                                       ______________________________________                                        TEDA/H.sub.3 BO.sub.3.sup.a                                                                 liquid     <0.10 mils/yr                                        TEDA/H.sub.3 BO.sub.3                                                                       liquid      0.11 mils/yr                                        TEDA/H.sub.3 BO.sub.3                                                                       liquid/vapor                                                                             --                                                   TEDA/H.sub.3 BO.sub.3                                                                       vapor      <0.10 mils/yr                                        TEDA/H.sub.3 BO.sub.3                                                                       vapor      <0.10 mils/yr                                        DABCO 8154.sup.b                                                                            liquid      12.2 mils/yr                                        DABCO 8154    liquid      10.9 mils/yr                                        DABCO 8154    liquid/vapor                                                                             --                                                   DABCO 8154    vapor      <0.10 mils/yr                                        DABCO 8154    vapor      <0.10 mils/yr                                        BL-22/H.sub.2 BO.sub.3.sup.c                                                                liquid     <0.10 mils/yr                                        BL-22/H.sub.2 BO.sub.3                                                                      liquid                                                          BL-22/H.sub.2 BO.sub.3                                                                      liquid/vapor                                                                             --                                                   BL-22/H.sub.2 BO.sub.3                                                                      vapor      <0.10 mils/yr                                        BL-22/H.sub.2 BO.sub.3                                                                      vapor                                                           DABCO BL-17.sup.d                                                                           liquid        4 mils/yr                                         DABCO BL-17   liquid                                                          DABCO BL-17   liquid/vapor                                                                             significant                                                                   corrosion                                                                     visible etching                                                               at interface                                                                  (≈1/16-1/8 deep)                             DABCO BL-17   vapor      <0.10 mils/yr                                        DABCO BL-17   vapor                                                           ______________________________________                                         .sup.a Example 4 catalyst                                                     .sup.b Acid blocked catalyst                                                  .sup.c Example 1 catalyst                                                     .sup.d Acid blocked catalyst                                             

We have also found that these reduced odor tertiary amine/boron catalystcompositions provide physical property improvements. The glycerol borateacid/TEDA composition described in U.S. Pat. No. 3,113,515 affordedsignificant foam shrinkage in uncrushed molded foams. We have found thatTEDA/boric acid compositions in water do not cause such shrinkage infive vent, hand-mixed molded foams.

COMPARATIVE EXAMPLE 28

The control catalyst, 1.0 pphp DABCO 33LV catalyst and 2.8 pphp water(3.2 pphp total water) were added to master batch formulation II. Foamswere made over 8 days by combining this formulation with 43.09 pphp ofan 80:20 mixture of 2,4- and 2,6-TDI (1.05 molar ratio of isocyanate toactive hydrogen functionality), mixing well for 4 sec, pouring over 11sec into a five vent mold heated to 140° F. (60° C.), and allowing tocure for 4 min prior to demold. Foams were removed from the mold withoutcrushing and allowed to age at least 24h before physical properties weremeasured. Foam shrinkage was evaluated by measuring the molded foamthickness at its minimum and comparing to the actual mold depth (114mm).

    ______________________________________                                        extrusion (sec)       32.1 (av)                                               string gel (sec)      39.6 (av)                                               foam weight (g)       197.0 (av)                                              foam thickness (mm)   107   (av)                                              foam shrinkage (%)    6   (av)                                                ______________________________________                                    

COMPARATIVE EXAMPLE 29

A comparative catalyst, 1.10 pphp of TEDA/glycerol borate acid preparedaccording to Comparative Example 25 (containing 30 wt % TEDA), and 2.8pphp water (3.2 pphp total water) were added to master batch formulationII. Foams were made over 8 days by combining this formulation with 43.79pphp of an 80:20 mixture of 2,4- and 2,6-TDI (1.05 molar ratio ofisocyanate to active hydrogen functionality), mixing well for 4 sec,pouring over 11 sec into a five vent mold heated to 140° F. (60° C.),and allowing to cure for 4 min prior to demold. Foams were removed fromthe mold without crushing and allowed to age at least 24h beforephysical properties were measured. Foam shrinkage was evaluated bymeasuring the molded foam thickness at its minimum and comparing to theactual mold depth (114 mm).

    ______________________________________                                        extrusion (sec)       34.3 (av)                                               string gel (sec)      43.4 (av)                                               foam weight (g)       191.6 (av)                                              foam thickness (mm)   98   (av)                                               foam shrinkage (%)    14   (av)                                               ______________________________________                                    

EXAMPLE 30

An experimental catalyst, 1.00 pphp of a 50 wt % aqueous solution of 1:1TEDA/boric acid (containing 33 wt % TEDA) from Example 26, and 2.3 pphpwater (3.2 pphp total water) were added to master batch formulation II.Foams were made over 8 days by combining this formulation with 42.18pphp of an 80:20 mixture of 2,4- and 2,6-TDI (1.05 molar ratio ofisocyanate to active hydrogen functionality), mixing well for 4 sec,pouring over 11 sec into a five vent mold heated to 140° F. (60° C.),and allowing to cure for 4 min prior to demold. Foams were removed fromthe mold without crushing and allowed to age at least 24h beforephysical properties were measured. Foam shrinkage was evaluated bymeasuring the molded foam thickness at its minimum and comparing to theactual mold depth (114 mm).

    ______________________________________                                        extrusion (sec)       31.6 (av)                                               string gel (sec)      39.4 (av)                                               foam weight (g)       192.3 (av)                                              foam thickness (mm)   111   (av)                                              foam shrinkage (%)    2.6 (av)                                                ______________________________________                                    

These new catalyst compositions also have significan reduced amine odorcompared to standard catalyst compositions containing volatile tertiaryamines. We suspect that the presence of the boron compound in thecatalyst solution minimizes release of amine into the atmosphere.

EXAMPLE 31

A 1:1 molar mixture of 3-quinuclidinol (3-QND) and boric acid wasprepared by dissolving 3-QND (15 g) in water (22.3 g) at roomtemperature. The boric acid (7.4 g) was added and dissolved to give aclear, pale yellow solution. The resulting solution was 33 wt % 3-QND.

COMPARATIVE EXAMPLES 32 and 34 AND EXAMPLES 33 and 35

PHD polyol based formulations were prepared from the master batchformulation, water (adjusted in each case to keep the total water levelequal to 3.2 pphp) and varying combinations of 3-QND,N,N,N'-trimethyl-N-hydroxyethylbis(aminoethyl)ether (Texacat®ZF-10) andan experimental catalyst prepared according to Example 31. Theformulations were mixed well for 30 sec prior to adding 42 pphp of an80:20 mixture of 2,4- and 2,6-TDI (1.05 molar ratio of isocyanate toactive hydrogen functionality). After mixing well for 4 sec, themixtures were poured over 11 sec into a five vent mold heated to 140° F.(60° C.) and allowed to cure for 4 min prior to demold. The followingTable D summarizes the results.

                  TABLE D                                                         ______________________________________                                                Comp            Comp Ex. 34                                                                              Ex 35                                              Ex 32  Ex 33    3-QND.sup.b /                                                                            Ex 31 cat/                                         3-QND.sup.a                                                                          Ex 31 cat                                                                              ZF-10      ZF-10                                      ______________________________________                                        Catalyst (pphp)                                                                         0.9      0.9      0.41/0.23                                                                              0.61/0.12                                Contained 0.3      0.3      0.43     0.32                                     amine (pphp)                                                                  Extrusion (sec)                                                                         46.0     30.1     35.1     33.1                                     String Gel (sec)                                                                        55.6     38.5     43.6     45.0                                     Foam Weight                                                                             199.8    188.4    196.9    186.2                                    (g)                                                                           ______________________________________                                         .sup.a delivered as a 33 wt % solution in ethylene glycol                     .sup.b delivered as a 50 wt % solution in water                          

Comparative Example 32 and Example 33 show that at an equimolar aminelevel, the addition of boric acid dramatically reduces extrusion and geltimes for the foaming process. Comparative Example 34 and Example 35show that equivalent reactivity during the foaming process can beachieved at lower amine use level in the presence of boric acid.

EXAMPLE 36

Gas chromatoqraphy head space analysis was performed to determine aminecontent in the atmosphere above various catalyst solutions. A five gramaliquot of each sample was weighed into headspace vials and kept at aconstant 30° C. for at least one hour before being analyzed. A 1-ccaliquot of the headspace was injected onto an HP-5 capillary columninterfaced to a flame ionization detector. Quantitation was obtainedusing an external standard procedure. The amine/boron catalyst solutionswere compared to commercial catalyst compositions such as DABCO 33-LVand DABCO BL-11 catalysts. The data in Table E shows a lower amineconcentration in the head space over the compositions of the inventionthan over the commercial catalysts.

                  TABLE E                                                         ______________________________________                                                           Amine concentration                                        Catalyst           in head space                                              ______________________________________                                        New catalyst compositions:                                                    Example 1 catalyst 2.2 mol ppm                                                Example 4 catalyst 1.8 mol ppm                                                Example 5 catalyst 2.4 mol ppm                                                Example 6 catalyst 3.6 mol ppm                                                Commercial Catalysts:                                                         DABCO 33-LV        145.9 mol ppm                                              DABCO BL-11        114.1 mole ppm                                             ______________________________________                                    

STATEMENT OF INDUSTRIAL APPLICATION

The present invention provides an amine catalyst composition for makingpolyurethane foam products which exhibits reduced odor, reducedviscosity and lower corrosivity.

We claim:
 1. A catalyst composition consisting essentially of a hydroxylgroup-containing tertiary amine urethane catalyst and a boron compoundof the formula

    R.sub.n B(OH).sub.3-n

where n=0 or 1, and R=C₁ -C₈ alkyl, C₅ -C₈ cycloalkyl or C₆ -C₁₀ aryl.2. The catalyst composition of claim 1 in which the tertiary amine isN,N,N'-trimethyl-N'-hydroxyethylethylene-diamine,N,N-dimethylethanolamine,N,N,N'-trimethyl-N,-hydroxy-ethylbis(aminoethyl)ether or3-quinuclidinol.
 3. The catalyst composition of claim 1 in which the 15tertiary amine is 3-quinuclidinol.
 4. The catalyst composition of claim1 in which the boron compound is boric acid, phenylboronic acid orisopropylboronic acid.
 5. The catalyst composition of claim 1 in whichthe boron compound is boric acid.
 6. The catalyst composition of claim 3in which the boron compound is boric acid.
 7. The catalyst compositionof claim 1 in which the tertiary nitrogen to boron is a 1:0.1 to 1:10molar ratio.
 8. The catalyst composition of claim 1 in which thetertiary nitrogen to boron is a 1:0.5 to 1:2 molar ratio.